Trevor Bauer did not endear himself to some Diamondbacks teammates or management. / Rob Schumacher Rob Schumacher/The Republic

by Bob Nightengale, USA TODAY Sports

by Bob Nightengale, USA TODAY Sports

It is one of the swiftest and most dramatic plunges of a young player's value since prized New York Yankees prospect Brien Taylor got into a bar fight in 1993.

Six months ago, Trevor Bauer was making his celebrated major-league debut, a year after the Arizona Diamondbacks took him with the third pick in the draft. He was going to be a star. Certainly the ace of the staff.

His personal coach and long-toss guru, Alan Jaeger, predicted Bauer would be a multiple Cy Young Award winner.

The Diamondbacks made it clear Tuesday night they hardly share the same sentiments.

Two middle relievers and a washed-up first base prospect were thrown into the mix, but it was essentially Bauer for Gregorius from the Diamondbacks' standpoint.

Gregorius, 22, may not remind anyone but Diamondbacks GM Kevin Towers of a young Derek Jeter, and scouts say he is a strong defender with a terrific arm and energy level. It's just that no one has any idea whether he'll hit enough to be a front-line shortstop. And that made parting with a prospect of Bauer's caliber extremely curious.

"He's a big-league shortstop right now,'' said Reds' scouting vice president Bill Bavasi, whose club landed outfielder Shin-Soo Choo in the deal. "He's got a ways to go with the bat, but he's not that far off. It's not defined yet what kind of player he'll be, but he's a great kid, and his intelligence and make-up is off the charts.''

Still, this not All-Star shortstop Elvis Andrus or prized prospect Jurickson Profar from the Texas Rangers. This is not shortstop Andrelton Simmons from the Atlanta Braves. This isn't even Asdrubal Cabrera from the Indians.

This is Gregorius, ranked the sixth-best prospect in the Reds' organization by Baseball America, with a career .271/.323/.376 slash line in five minor-league seasons.

So what's up? Why would Bauer, the Diamondbacks' minor-league pitcher of the year after going 12-2 with a 2.42 ERA in 22 starts at Class AA Mobile and Triple A Reno with 200 strikeouts in 156 innings be discarded like a backup catcher? He didn't have a scintilla of arm problems.

Asked if Bauer's personality or controversial long-toss program factored in the trade, Towers said simply, "My guess is this kid's going to have a very good career and my hope is that this is a win-win for both sides. We were fortunate that we have a lot of pitching depth that allowed us to make this sort of deal."

Sorry, no one is buying it. You don't guarantee a player $4.45 million 17 months ago, with a $3.4 million signing bonus, and boot him out of the organization after four major-league starts, even if they did result in a 6.06 ERA.

"He just had a really tough year with his teammates,'' Diamondbacks president Derrick Hall told USA TODAY Sports. Hall offered no specifics but confirmed that Bauer apologized to several veteran teammates this winter for his attitude.

Diamondbacks 2011 All-Star catcher Miguel Montero, who couldn't be reached Wednesday, was the most vocal critic of Bauer. He was incensed with the number of times Bauer shook off his signs, including the first pitch of his first major-league game against the Atlanta Braves. Montero publicly vented after Bauer's second start against the Los Angeles Dodgers when Bauer told reporters that he needed to tell Montero how he liked to call a game.

"What?'' Montero said. "He's going to tell me how to do my job?''

Bauer, who majored in mechanical engineering at UCLA, is a loner, several Diamondbacks told USA TODAY Sports. He resisted advice from the coaching staff. He tuned out the veterans. He even refused to listen to younger teammates. He was going to do things his way.

Diamondbacks players and officials contacted Wednesday recalled the night Bauer made his major-league debut June 28. It was 97 degrees in Atlanta. Bauer hit in the first batting-practice group. But instead of cooling off and relaxing, he went to the left-field corner and began stretching. He then began throwing long-toss from the left-field pole to right-center field. One hour still remained before the first pitch, and Bauer was drenched in perspiration, throwing pitch after pitch during his warm-ups. They looked at him like he was crazy. Hs debut lasted four innings, throwing 42 of his 74 pitches for strikes.

The Diamondbacks kept trying to get through to him, realizing he is just 21. They kept waiting for him to grow up. They scolded him for using his Twitter account 30 minutes before one game. They groaned when he mocked President Obama during the debates in October, tweeting: "Obama looked childish and petty tonight. I'm ashamed that he is commander in chief of this great nation.''

And when Bauer threw a fit after being pulled from the Class AAA championship game against Pawtucket, one out short of qualifying for the win in Reno's 10-3 victory, they punished him. Bauer, with Towers in attendance, was forced to apologize to his teammates. They refused to bring him to the big leagues with the other September call-ups. It turned out to be the last pitch he'd ever throw in the Diamondbacks organization.

Now, it's the Indians' turn to try to figure him out.

"We did our due diligence,'' Cleveland GM Chris Antonetti told USA TODAY Sports. "We think Trevor has a lot of potential. He's a very young pitcher, with not a whole lot of professional development.

"I've talked to him twice already since the trade, and we're getting to know him. He has a good feel about our organization, our thoughts, our philosophies. We spent a lot of time when it came to him in the draft. I talked to him two hours then. We talked about his career, his warm-up routine. He's a very cerebral guy, with very deep thoughts when it comes to pitching and conditioning.''

Bauer, begrudgingly permitted to do his eccentric long-toss program with Arizona, will be allowed to continue it in Cleveland.

"We're not very restrictive, depending on the individual,'' Antonetti said. "Then again, I don't think we've had guys long-toss 400 feet before. . .We still need to learn about each other.''

The Diamondbacks will be watching. Maybe this is the wake-up call he needs. Maybe this will force him to do some soul-searching, realize his fastball has dropped from 95-97 mph to 91-92 mph, and recognize that big-league hitters are a lot more patient than pimple-faced college kids.

If not, he'll be nothing more than another overhyped, first-round casualty. The annals of baseball are full of them.